FAULT

(CRACK) [noun] [C] [specialized] - a crack in the Earth's surface where the rock has divided into two parts which move against each otherA fault line is a line of weakness in the rocks of the Earth's surface, where an earthquake is most likely to happen.A fault line within a society, a political party or another organization is a division or disagreement within it that divides it into different groups.The party is still divided along the same fault lines that split it in the past.